content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
   * in the United States and other countries.]
   *
   * ---------------
   * PanHandler.java
   * ---------------
   * (C) Copyright 2009-2013, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes:
   * --------
   * 11-Jun-2009 : Version 1 (DG);
   *
   */
  
  package org.jfree.chart.panel;
  
  import java.awt.Cursor;
  import java.awt.Point;
  import java.awt.event.MouseEvent;
  import java.awt.geom.Rectangle2D;
  
  import org.jfree.chart.ChartPanel;
  import org.jfree.chart.JFreeChart;
  import org.jfree.chart.plot.Pannable;
  import org.jfree.chart.plot.Plot;
  import org.jfree.chart.plot.PlotOrientation;
  import org.jfree.chart.plot.PlotRenderingInfo;
  
  /**
   * Handles panning operations in a {@link ChartPanel} if the plot supports
   * them.
   */
  public class PanHandler extends AbstractMouseHandler {
      
      /** a generated serial id. */
      private static final long serialVersionUID = -2454906267665359292L;
  
      /**
       * Temporary storage for the width and height of the chart
       * drawing area during panning.
       */
      private double panW, panH;
  
      /** The last mouse position during panning. */
      private Point panLast;
  
      public PanHandler(int modifier) {
          super(modifier);
          this.panLast = null;
      }
      
      public PanHandler() {
          super();
          this.panLast = null;
      }
  
      @Override
      public void mousePressed(MouseEvent e) {
          ChartPanel panel = (ChartPanel) e.getSource();
          Plot plot = panel.getChart().getPlot();
          if (!(plot instanceof Pannable)) {
              panel.clearLiveMouseHandler();
              return;  // there's nothing for us to do (except unregistering)
          }
          Pannable pannable = (Pannable) plot;
          if (pannable.isDomainPannable() || pannable.isRangePannable()) {
              Rectangle2D screenDataArea = panel.getScreenDataArea(e.getX(),
                      e.getY());
              if (screenDataArea != null && screenDataArea.contains(
                      e.getPoint())) {
                  this.panW = screenDataArea.getWidth();
                  this.panH = screenDataArea.getHeight();
                  this.panLast = e.getPoint();
                  panel.setCursor(Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR));
              }
          }
          // the actual panning occurs later in the mouseDragged() method
      }
  
      @Override
      public void mouseDragged(MouseEvent e) {
          ChartPanel panel = (ChartPanel) e.getSource();
  
          if (this.panLast == null) {
              //handle panning if we have a start point else unregister
              panel.clearLiveMouseHandler();
              return;
          }
  
          JFreeChart chart = panel.getChart();
          double dx = e.getX() - this.panLast.getX();
          double dy = e.getY() - this.panLast.getY();
          if (dx == 0.0 && dy == 0.0) {
              return;
          }
          double wPercent = -dx / this.panW;
          double hPercent = dy / this.panH;
          boolean old = chart.getPlot().isNotify();
          chart.getPlot().setNotify(false);
          Pannable p = (Pannable) chart.getPlot();
          PlotRenderingInfo info = panel.getChartRenderingInfo().getPlotInfo();
          if (p.getOrientation() == PlotOrientation.VERTICAL) {
              p.panDomainAxes(wPercent, info, this.panLast);
              p.panRangeAxes(hPercent, info, this.panLast);
          }
          else {
              p.panDomainAxes(hPercent, info, this.panLast);
              p.panRangeAxes(wPercent, info, this.panLast);
          }
          this.panLast = e.getPoint();
          chart.getPlot().setNotify(old);
      }
  
      @Override
      public void mouseReleased(MouseEvent e) {
          ChartPanel panel = (ChartPanel) e.getSource();
          //if we have been panning reset the cursor
          //unregister in any case
          if (this.panLast != null) {
              panel.setCursor(Cursor.getDefaultCursor());
          }
          this.panLast = null;
          panel.clearLiveMouseHandler();
      }
  
      /**
       * @see AbstractMouseHandler#isLiveHandler()
       */
      public boolean isLiveHandler() {
          return true;
      }
  
  }
  